In his just delivered State of the Union address, President Barack Obama made certain specific and predictable references to prominent international issues, most notably U.S. disengagement from Afghanistan, Iran's still-developing bomb, and North Korea's latest nuclear tests. He even urged improving American cyber-defenses.

What was missing, however, was a conspicuously coherent and generalized focus on U.S. strategic doctrine. Oddly, at absolutely no point in the speech, were Mr. Obama's carefully chosen references linked explicitly, systematically, and purposefully to more usefully comprehensive visions of American nuclear strategy.

Yes, predictably, the president renewed his seemingly sensible drive for cuts in nuclear arms, but this almost-visceral renewal was only about number, not doctrine.

Yes, we already knew that this president doesn't like nuclear weapons, and that he thinks they are inherently corrosive and destabilizing.

But there are times when such weapons can genuinely protect particular nations from otherwise likely aggressions. Indeed, sometimes these weapons can serve a distinctly peacekeeping function. This should be obvious to anyone who can recall that the Cold War never gave way to actual armed conflict between the nuclear superpowers.

In the past, of course, Barack Obama has spoken openly in favor of “a world free of nuclear weapons." On its face, such talk sounds reasonable and persuasive. Still, this quaintly high-minded objective remains naive and wrongheaded. Global denuclearization is a plainly improbable, and at least a selectively undesirable, goal.

For all of the usual reasons concerning international distrust and uncertainty, this goal could never be achieved. Moreover, as it pertains to certain especially vulnerable nations (e.g., Israel), and also to especially powerful nations (e.g., the United States), it should never be achieved.

Without nuclear weapons, Israel could have no residually meaningful way to deter major enemy aggressions.

With too small, and/or too deteriorated an arsenal of nuclear weapons, the U.S. could ultimately find itself without a credible deterrent against a variety of both present and future nuclear adversaries.

The United States, the president ought to have announced, needs to work promptly and diligently toward something far more thoughtful and subtle than formula-driven, across the board reductions in nuclear arms. His declared goal should not be a world that will simply have fewer nuclear weapons, but rather one that will be less susceptible to all conceivable forms of total war and mega-terror. The goal ought not to be a concocted or idealized world, a fictive vision premised on the banal syntax of amateur thinking, a so-called "world without nuclear weapons."

At this very important annual speech, an opportunity was lost. The State of the Union address could have presented an optimal moment for introducing reinvigorated and nuanced military thinking. For the future, after all, ad hoc and disjointed U.S. responses to individual threats from foreign countries will assuredly not be enough. Such responses could even represent an invitation to further and more expansive American military failures.

In essence, the president should have declared that we now require a finely-codified plan for national security that can deal capably with various Jihadist adversaries, both state and sub-state, and also with prospective and still-formidable nuclear foes in Russia, North Korea, China, Iran, and possibly a plausibly post-coup Pakistan.

During the 1950s, the United States first began to institute various doctrines of nuclear deterrence. At that time, at least geopolitically, the world was a much simpler place. Global power distributions were then tightly bipolar; the indisputable enemy was the Soviet Union.

At that time, American national strategy was founded on a core policy of “massive retaliation.” Later, especially during the Kennedy years, this narrowly-circumscribed stance was modified by something then labeled “flexible response.”

Today, a much more complex landscape reveals multiple, inter-penetrating, and sometimes synergistic axes of conflict. Significantly, there are now almost four times as many countries as had existed back in 1945. In this expressly multipolar world, Russia is once again a justifiably major security concern. In the earlier post-Soviet era, we may recall, the Russian threat had initially been downgraded in the always-important rank ordering of vital U.S. strategic concerns.

Russian President Vladimir Putin remains fearful of possibly still-planned U.S. ballistic missile defenses in Europe. In his view, a perspective that actually reflects a fairly standard or classical view of nuclear deterrence, such active defenses would jeopardize the stability of our changing balance of power. This is because the inherent logic of nuclear deterrence (Manhattan Project physicist J. Robert Oppenheimer had spoken of the superpowers as "two scorpions in a bottle") is based on the idea of "mutual vulnerability."

To shape an authentically improved U.S, strategic doctrine, President Obama will need to reconsider fundamental matters of nuclear targeting. Among other things, such a reconsideration would examine certain basic differences between the targeting of enemy civilians and cities (“countervalue” targeting), and the targeting of enemy military assets and infrastructures (“counterforce” targeting).

Originally, the essence of “massive retaliation” and its corollary, MAD, had been counter value targeting. Presently, in those relatively promising circumstances where enemy rationality might still be reliably assumed, effective U.S. deterrence could once again require readily recognizable policies of counter city targeting. In circumstances where we would appear to face non-rational state adversaries, however, purposeful deterrence calculations could prove markedly different, and substantially more difficult.

Unless President Obama finally begins to give U.S. strategic deterrence the attention and resources it requires, we could place ourselves at a renewed national risk of assorted large-scale enemy attacks.

Science is a method of reaching conclusions. In any science, including national nuclear strategy, generality is a trait of all meaning. Accordingly, this is not the time for an American president to revive the deceptively pleasing resonance of a "nuclear weapons free world." Nor is this the correct moment to focus on certain individual nuclear threats as if they were all somehow singular, ad hoc, and unique.

Although ignored in the State of the Union, now is the proper time to fashion a broadly systematic and informed U.S. strategic doctrine.

This demanding task will have to address still-impending prospects for American preemption, as well as improved methods for distinguishing adversaries (state and sub-state) according to whether they are presumed to be rational, irrational, or “mad.” It will also need to consider certain more-or-less intersecting elements of nuclear deterrence, active defense, cyber-defense, and cyber-warfare. And it will have to examine such elements within the far wider and more layered questions of pertinent international law, including authoritative criteria for determining (1) "anticipatory self-defense;" and (2) nonproliferation regime enforcement.

Within the Department of Defense and larger U.S. defense community, a protracted lack of emphasis on nuclear strategy and tactics has already left our military unprepared for some of the most threatening existential scenarios. To suitably confront this deficiency, one generated, in part, by our continuing involvement in non-productive and tangibly unwinnable wars, the president needs to commission a special and largely re-imagined Nuclear Posture Review. Among other things, this hard-nosed and dialectical assessment should emphasize new program designs for advanced nuclear weapons; modernization of needed nuclear infrastructures; and more consciously precise calibrations of American nuclear strength to different levels and venues of enemy threat.

Toward the end of his speech, President Obama movingly listed a number of compassionate intranational changes that could help make America a safer and more durable society. Not included in this list, however, was the single most important change of all - the creation of a promising plan for the physical protection of the United States from egregious international harms. Nowhere was there any mention of need for a viable strategic doctrine.

For America, strategic doctrine is an utterly indispensable net. Only those presidents who dare to cast, will catch.

Louis René Beres (Ph.D., Princeton, 1971) is the author of many major books and articles on nuclear strategy and nuclear war, including several very early works onnuclear terrorism. His writing has appeared in Special Warfare and Parameters, publications of the U.S. Department of Defense, and also in International Security(Harvard); World Politics (Princeton); The Israel Journal of Foreign Affairs; Armed Forces and Society; and International Journal of Intelligence and Counterintelligence. In Israel, he was Chair of Project Daniel (PM Sharon, 2003). He is the author, inter alia, of Apocalypse: Nuclear Catastrophe in World Politics (University of Chicago Press, 1980); Mimicking Sisyphus: America's Countervailing Nuclear Strategy (Heath/Lexington, 1983); Security or Armageddon: Israel’s Nuclear Strategy (Heath/ Lexington, 1986); and Terrorism and Global Security: The Nuclear Threat (Westview Special Studies in National and International Terrorism, 1987). Professor Beres was born in Zürich, Switzerland, on August 31, 1945.